Abstract: A micro-electrical-mechanical device comprises: a transducer arrangement having at least a membrane being mounted with respect to a substrate; and electrical interface means for relating electrical signals to movement of the membrane; in which the transducer arrangement comprises stress alleviating formations which at least partially decouple the membrane from expansion or contraction of the substrate.

Abstract: A MEMS device comprising a flexible membrane that is free to move in response to pressure differences generated by sound waves. A first electrode mechanically coupled to the flexible membrane, and together form a first capacitive plate. A second electrode mechanically coupled to a generally rigid structural layer or back-plate, which together form a second capacitive plate. A back-volume is provided below the membrane. A first cavity located directly below the membrane. Interposed between the first and second electrodes is a second cavity. A plurality of bleed holes connected the first cavity and the second cavity. Acoustic holes are arranged in the back-plate so as to allow free movement of air molecules, such that the sound waves can enter the second cavity. The first and second cavities in association with the back-volume allow the membrane to move in response to the sound waves entering via the acoustic holes in the back-plate.

Abstract: A MEMS device comprising a flexible membrane that is free to move in response to pressure differences generated by sound waves. A first electrode mechanically coupled to the flexible membrane, and together form a first capacitive plate. A second electrode mechanically coupled to a generally rigid structural layer or back-plate, which together form a second capacitive plate. A back-volume is provided below the membrane. A first cavity located directly below the membrane. Interposed between the first and second electrodes is a second cavity. A plurality of bleed holes connect the first cavity and the second cavity. Acoustic holes are arranged in the back-plate so as to allow free movement of air molecules, such that the sound waves can enter the second cavity. The first and second cavities in association with the back-volume allow the membrane to move in response to the sound waves entering via the acoustic holes in the back-plate.

Abstract: A MEMS device, for example a capacitive microphone, comprises a flexible membrane 11 that is free to move in response to pressure differences generated by sound waves. A first electrode 13 is mechanically coupled to the flexible membrane 11, and together form a first capacitive plate of the capacitive microphone device. A second electrode 23 is mechanically coupled to a generally rigid structural layer or back-plate 14, which together form a second capacitive plate of the capacitive microphone device. The capacitive microphone is formed on a substrate 1, for example a silicon wafer. A back-volume 33 is provided below the membrane 11, and is formed using a “back-etch” through the substrate 1. A first cavity 9 is located directly below the membrane 11, and is formed using a first sacrificial layer during the fabrication process. Interposed between the first and second electrodes 13 and 23 is a second cavity 17, which is formed using a second sacrificial layer during the fabrication process.

Abstract: A micro-electrical-mechanical device comprises: a transducer arrangement having at least a membrane being mounted with respect to a substrate; and electrical interface means for relating electrical signals to movement of the membrane; in which the transducer arrangement comprises stress alleviating formations which at least partially decouple the membrane from expansion or contraction of the substrate.

Abstract: A MEMS device, for example a capacitive microphone, comprises a flexible membrane 11 that is free to move in response to pressure differences generated by sound waves. A first electrode 13 is mechanically coupled to the flexible membrane 11, and together form a first capacitive plate of the capacitive microphone device. A second electrode 23 is mechanically coupled to a generally rigid structural layer or back-plate 14, which together form a second capacitive plate of the capacitive microphone device. The capacitive microphone is formed on a substrate 1, for example a silicon wafer. A back-volume 33 is provided below the membrane 11, and is formed using a “back-etch” through the substrate 1. A first cavity 9 is located directly below the membrane 11, and is formed using a first sacrificial layer during the fabrication process. Interposed between the first and second electrodes 13 and 23 is a second cavity 17, which is formed using a second sacrificial layer during the fabrication process.